Fix metadata buffer wait/wakeup

[lttng-modules.git] / lib / ringbuffer / ring_buffer_frontend.c

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index db33d04cba8dc7ba8f23d4b90ee0658cbe1888c4..6a4c241e84677e3f14f14aee282d0a00a418830a 100644 (file)
--- a/lib/ringbuffer/ring_buffer_frontend.c
+++ b/lib/ringbuffer/ring_buffer_frontend.c
@@ -203,6 +203,7 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
        }
 
        init_waitqueue_head(&buf->read_wait);
+       init_waitqueue_head(&buf->write_wait);
        raw_spin_lock_init(&buf->raw_tick_nohz_spinlock);
 
        /*
@@ -867,6 +868,8 @@ EXPORT_SYMBOL_GPL(lib_ring_buffer_snapshot);
 
 /**
  * lib_ring_buffer_put_snapshot - move consumed counter forward
+ *
+ * Should only be called from consumer context.
  * @buf: ring buffer
  * @consumed_new: new consumed count value
  */
@@ -888,6 +891,8 @@ void lib_ring_buffer_move_consumer(struct lib_ring_buffer *buf,
        while ((long) consumed - (long) consumed_new < 0)
                consumed = atomic_long_cmpxchg(&buf->consumed, consumed,
                                               consumed_new);
+       /* Wake-up the metadata producer */
+       wake_up_interruptible(&buf->write_wait);
 }
 EXPORT_SYMBOL_GPL(lib_ring_buffer_move_consumer);